Structural and optical characterization of ZnS ultrathin films prepared by low-temperature ALD from diethylzinc and 1.5-pentanedithiol after various annealing treatments

Maksymilian Włodarski, Urszula Chodorow, Stanisław Jóźwiak, Matti Putkonen, Tomasz Durejko (Corresponding Author), Timo Sajavaara, Małgorzata Norek (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures ≥400 °C and annealing time ≥2 h, and 1:1 stoichiometry was obtained when annealed at 500 °C for 4 h. ZnS crystallized into small crystallites (1-7 nm) with cubic sphalerite structure, which remained stable under the applied annealing conditions. The size of the crystallites (D) tended to decrease with annealing temperature, in agreement with the EDS data (decreased content of both S and Zn with annealing temperature); the D for samples annealed at 600 °C (for the time ≤2 h) was always the smallest. Both reflectivity and ellipsometric spectra showed characteristics typical for quantum confinement (distinct dips/peaks in UV spectral region). It can thus be concluded that the amorphous ZnS layer obtained at a relatively low temperature (150 °C) from organic S precursor transformed into the layers built of small ZnS nanocrystals of cubic structure after annealing at a temperature range of 300-600 °C under Ar atmosphere.

Original languageEnglish
Article number3212
JournalMaterials
Volume12
Issue number19
DOIs
Publication statusPublished - 2019
MoE publication typeA1 Journal article-refereed

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Atomic layer deposition
Ultrathin films
Annealing
Temperature
Crystallites
Stoichiometry
Quantum confinement
diethylzinc
Sulfur
Nanocrystals
Zinc
Energy dispersive spectroscopy
Thin films

Keywords

  • Annealing
  • Atomic layer deposition (ALD)
  • Optical properties
  • ZnS thin films

Cite this

Włodarski, Maksymilian ; Chodorow, Urszula ; Jóźwiak, Stanisław ; Putkonen, Matti ; Durejko, Tomasz ; Sajavaara, Timo ; Norek, Małgorzata. / Structural and optical characterization of ZnS ultrathin films prepared by low-temperature ALD from diethylzinc and 1.5-pentanedithiol after various annealing treatments. In: Materials. 2019 ; Vol. 12, No. 19.
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abstract = "The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures ≥400 °C and annealing time ≥2 h, and 1:1 stoichiometry was obtained when annealed at 500 °C for 4 h. ZnS crystallized into small crystallites (1-7 nm) with cubic sphalerite structure, which remained stable under the applied annealing conditions. The size of the crystallites (D) tended to decrease with annealing temperature, in agreement with the EDS data (decreased content of both S and Zn with annealing temperature); the D for samples annealed at 600 °C (for the time ≤2 h) was always the smallest. Both reflectivity and ellipsometric spectra showed characteristics typical for quantum confinement (distinct dips/peaks in UV spectral region). It can thus be concluded that the amorphous ZnS layer obtained at a relatively low temperature (150 °C) from organic S precursor transformed into the layers built of small ZnS nanocrystals of cubic structure after annealing at a temperature range of 300-600 °C under Ar atmosphere.",
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Structural and optical characterization of ZnS ultrathin films prepared by low-temperature ALD from diethylzinc and 1.5-pentanedithiol after various annealing treatments. / Włodarski, Maksymilian; Chodorow, Urszula; Jóźwiak, Stanisław; Putkonen, Matti; Durejko, Tomasz (Corresponding Author); Sajavaara, Timo; Norek, Małgorzata (Corresponding Author).

In: Materials, Vol. 12, No. 19, 3212, 2019.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Structural and optical characterization of ZnS ultrathin films prepared by low-temperature ALD from diethylzinc and 1.5-pentanedithiol after various annealing treatments

AU - Włodarski, Maksymilian

AU - Chodorow, Urszula

AU - Jóźwiak, Stanisław

AU - Putkonen, Matti

AU - Durejko, Tomasz

AU - Sajavaara, Timo

AU - Norek, Małgorzata

PY - 2019

Y1 - 2019

N2 - The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures ≥400 °C and annealing time ≥2 h, and 1:1 stoichiometry was obtained when annealed at 500 °C for 4 h. ZnS crystallized into small crystallites (1-7 nm) with cubic sphalerite structure, which remained stable under the applied annealing conditions. The size of the crystallites (D) tended to decrease with annealing temperature, in agreement with the EDS data (decreased content of both S and Zn with annealing temperature); the D for samples annealed at 600 °C (for the time ≤2 h) was always the smallest. Both reflectivity and ellipsometric spectra showed characteristics typical for quantum confinement (distinct dips/peaks in UV spectral region). It can thus be concluded that the amorphous ZnS layer obtained at a relatively low temperature (150 °C) from organic S precursor transformed into the layers built of small ZnS nanocrystals of cubic structure after annealing at a temperature range of 300-600 °C under Ar atmosphere.

AB - The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures ≥400 °C and annealing time ≥2 h, and 1:1 stoichiometry was obtained when annealed at 500 °C for 4 h. ZnS crystallized into small crystallites (1-7 nm) with cubic sphalerite structure, which remained stable under the applied annealing conditions. The size of the crystallites (D) tended to decrease with annealing temperature, in agreement with the EDS data (decreased content of both S and Zn with annealing temperature); the D for samples annealed at 600 °C (for the time ≤2 h) was always the smallest. Both reflectivity and ellipsometric spectra showed characteristics typical for quantum confinement (distinct dips/peaks in UV spectral region). It can thus be concluded that the amorphous ZnS layer obtained at a relatively low temperature (150 °C) from organic S precursor transformed into the layers built of small ZnS nanocrystals of cubic structure after annealing at a temperature range of 300-600 °C under Ar atmosphere.

KW - Annealing

KW - Atomic layer deposition (ALD)

KW - Optical properties

KW - ZnS thin films

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